Venetian blinds are a well known covering for windows. Venetian blinds typically include a head rail, a bottom rail, and a plurality of blind slats. The head rail is usually made from a relatively strong and rigid metal, whereas the bottom rail and blind slats are made from thinner pieces of aluminum. Each of these blind components are designed to extend horizontally across a window space.
Window spaces, however, are built in a myriad of different widths. Therefore, there is a need for many different widths of Venetian blinds to suit the differing widths of window spaces. For many years it has been the practice to manufacture Venetian blinds on a custom basis. Each blind would be made with the width of the blind components to correspond to the width of the particular window for a particular customer. This procedure is relatively expensive because the process lacks any economies of scale. This custom process also requires a substantial amount of time to custom build blinds for each particular window.
In order to remedy this problem, various manufacturers have produced Venetian blind cutting machines that can trim Venetian blinds of various standard sizes to the desired width at the point of sale. With such machines, a customer wishing to purchase blinds from such an outlet would simply come in with the measurements of his or her windows, and select blinds from a stock of standard size blinds, which are slightly wider than the desired measurement. The retail store would then trim the ends of the blinds to the widths desired.
One example of this type of machine is the apparatus disclosed in Canadian Patent Application No. 2,136,519. The apparatus described in Canadian Patent Application No. 2,136,519 provides a blind cutting apparatus that uses a guillotine-type blade or shear to cut the head rail, and a second blade assembly to cut the bottom rail and blind slats. The Venetian blind components are passed through openings in a body until the components contact an adjustable end guide. The cutters for the head rail, the bottom rail and blind slats are juxtaposed to the body, and are all connected to a drive which, when actuated, causes the cutter for the head rail, and the cutter for the bottom rail and blind slats, to move along linear or straight paths to cut the Venetian blind components.
One shortcoming of the device disclosed in Canadian Patent Application No. 2,136,519 is the amount of force needed to cut the blind components. As stated, the head rail in a Venetian blind is typically made of a fairly strong metal that is difficult to cut. Since the apparatus of Canadian application No. 2,136,519 is configured to cut along a straight path, a substantial amount of force is required to complete the trimming operation. To supply the required force, the device shown is driven by a hydraulic mechanism. Such a power driven system increases the size and complexity of such a machine, as well as increases the expense of the machine. Also, because a blade is used, operators may experience substantial down time due to the need to change blades when worn out.
Another blind cutting apparatus is disclosed in U.S. Pat. Nos. 5,806,394; 6,178,857; and 6,196,099. Each of these patents discloses a cutting apparatus for Venetian blinds that, instead of a guillotine-type blade, uses a die plate to cut the head rail. The die plate is described as cutting the head rail linearly or along a straight path, preferably on a diagonal axis. In order to lessen the amount of force required by the operation to cut the blind components at any one time during the cutting process, these patents explain that the cutting of the head rail takes place in one part of the operation, and the cutting of the bottom rail and blind slats takes place in another. In other words, the cutting of the head rail and the cutting of the bottom rail and slat are performed at different times. Specifically, these patents describe a drive mechanism that, during the first part of the cutting stroke cuts the head rail, and during a second part of the cutting stroke cuts the bottom rail and blind slats. In order to accomplish this two part operation, the drive mechanism uses a complex slip pin and transmission is used to engage the die plate first, and then a blade assembly. While such an arrangement lessens the amount of force exerted during the cutting operation by limiting the number of blind components cut at any one time, additional parts are required to separate the cutting operations, which is inherently more expensive, and prone to breakdowns. Furthermore, since the cutting does not occur at the same time, there is a heightened potential for one or more of the blind components to shift during the cutting process, and therefore, result in an uneven cut.
Other prior art devices are also limited in the type of bottom rails which can easily be cut. While they can cut open or C-shaped bottom rails, they have difficulty cutting bottom rails which are closed, i.e., not having an opening.
What is needed is an apparatus that accurately and efficiently trims Venetian blinds in a simple machine, and that reduces the required amount of force required to complete the cutting operation. The present invention meets these desires and overcomes the shortcomings of the prior art.